British author Millar’s engrossing debut offers an unsettling, realistic view of friendships, gossip, and loneliness. Suzy Howard and Callie Roberts, who live on the same London street, appear to be best friends. They share child-care duties, and the affluent, obsessive Suzy often subsidizes their outings. The other neighborhood women have pointedly ignored Callie, a single mother who barely scrapes by and whose five-year-old daughter has a heart condition. When Callie decides to return to work, she hesitates to tell Suzy of her new job, causing a rift between them. A new neighbor, Debs Ribwell, a teacher with a dark history and fragile mental health, further jeopardizes their friendship. The narration shifts among the three women, slowly revealing the secrets that bind and alienate them. Despite all the time spent together, Suzy and Callie don’t really know each other, and the consequences put their children in peril. What starts as a quiet story about neighbors soon builds into a gripping psychological thriller. (July)